1. Field
The following description relates to mapping of an original packet flow in an overlay network. More specifically, the following description relates to an apparatus and method for supporting flow-based networking services throughout an entire virtual network by mapping an original packet flow before encapsulation, which is extracted from an underlying physical network corresponding to an encapsulated packet flow that passes through an overlay link, to a flow of the physical network, in the case where a network overlay-based virtual network system is configured on the physical network.
2. Description of the Related Art
For network virtualization, various network overlay technologies, such as virtual extensible LAN (VXLAN), generic routing encapsulation (GRE), and stateless transport tunneling (STT), have been proposed.
Most of the aforesaid network overlay technologies use an encapsulation mechanism whereby a designated header to contain virtual network information is defined then is combined with an original packet header.
Specifically, GRE and STT use the same encapsulation header as long as tunnels have the same end point, even when flows of packets that pass an overlay link are different from each other.
By contrast, in VXLAN, when original flows on a virtual network are different, UDP source port numbers of encapsulation headers are set differently, so that a physical network can recognize that the original flows are different.
However, in a situation where different networking services are required by different virtual networks, extraction of an original packet flow is needed so as to allow the physical network to identify to which virtual network a packet that passes through a tunneling segment is belonging.
In VXLAN, one tunnel end point (TEP)-to-TEP overlay link can be shared for any tunneling services for all virtual machines that are connected to pertinent TEPs, regardless of a virtual segment to which said virtual machines are belonging. In addition, since only an outer header of a packet can be viewed in an underlying physical network, it is not possible to check original flow information of said packet, and hence it is difficult to provide various original flow-based services in the physical network.